Schedule I Condensed Financial Information Of Parent Only (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Condensed Statement Of Operations Parent Company Only
Interest accrued - external	$ (598)	$ (628)	$ (656)
Early debt retirement costs	(271)	(606)	(1)
Other income (expense) - net	11	(12)	2
Income from continuing operations before income taxes	1,202	385	550
Provision for income taxes	124	114	204
Income (loss) from continuing operations	1,078	271	346
Income (loss) from discontinued operations	(417)	(1,193)	15
Net income (loss)	661	(922)	361
Basic earnings (loss) per common share:
Incom (loss) from continuing operations	$ 1.36	$ 0.17	$ 0.35
Income (loss) from discontinued operations	$ (0.72)	$ (2.05)	$ 0.14
Net income (loss)	$ 0.64	$ (1.88)	$ 0.49
Weighted-average shares (thousands)	588,553	584,552	581,674
Diluted earnings (loss) per common share:
Income (loss) from continuing operations	$ 1.34	$ 0.17	$ 0.35
Income (loss) from discontinued operations	$ (0.71)	$ (2.03)	$ 0.14
Net income (loss)	$ 0.63	$ (1.86)	$ 0.49
Weighted-average shares (thousands)	598,175	590,699	585,955
Assets, Current [Abstract]
Cash and cash equivalents	889	758
Other current assets	159	102
Total current assets	1,894	2,530
Property, plant and equipment - net	12,580	11,754
Other noncurrent assets	637	620
Total assets	16,502	24,972
Liabilities, Current [Abstract]
Long-term debt due within one year	353	508
Total current liabilities	1,675	2,574
Long-term debt	8,369	8,600
Deferred income taxes	1,660	1,738
Contingent liabilities and commitments
Equity: [Abstract]
Common stock	626	620
Total stockholders' equity	3,083	8,619	9,019	9,054
Total liabilities and stockholders' equity	16,502	24,972
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities	3,439	2,651	2,572
FINANCING ACTIVITIES:
Proceeds from long-term debt	3,172	5,129	595
Payments of long-term debt	(2,055)	(4,305)	(33)
Premiums paid on early debt retirements	(254)	(574)	0
Dividends paid	(457)	(284)	(256)
Other - net	42	17	(44)
Net cash provided (used) by financing activities	(342)	573	166
INVESTING ACTIVITIES:
Capital expenditures	(2,796)	(2,788)	(2,387)
Purchase of investments	233	488	142
Other - net	67	79	71
Net cash provided (used) by investing activities	(3,003)	(4,296)	(2,310)
Increase (decrease) in cash and cash equivalents	94	(1,072)	428
Cash and cash equivalents at beginning of year	758
Cash and cash equivalents at end of year	889	758
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted	38	39
Parent Company [Member]
Condensed Statement Of Operations Parent Company Only
Equity in earnings of consolidated subsidiaries	1,962	1,457	948
Interest accrued - external	(186)	(235)	(448)
Interest accrued - affiliate	(622)	(460)	(367)
Interest income - affiliate	84	76	285
Early debt retirement costs	(271)	(606)	(1)
Other income (expense) - net	(45)	(41)	(11)
Income from continuing operations before income taxes	922	191	406
Provision for income taxes	119	87	200
Income (loss) from continuing operations	803	104	206
Income (loss) from discontinued operations	(427)	(1,201)	79
Net income (loss)	376	(1,097)	285
Basic earnings (loss) per common share:
Incom (loss) from continuing operations	$ 1.36	$ 0.17	$ 0.35
Income (loss) from discontinued operations	$ (0.72)	$ (2.05)	$ 0.14
Net income (loss)	$ 0.64	$ (1.88)	$ 0.49
Weighted-average shares (thousands)	588,553	584,552	581,674
Diluted earnings (loss) per common share:
Income (loss) from continuing operations	$ 1.34	$ 0.17	$ 0.35
Income (loss) from discontinued operations	$ (0.71)	$ (2.03)	$ 0.14
Net income (loss)	$ 0.63	$ (1.86)	$ 0.49
Weighted-average shares (thousands)	598,175	590,699	585,955
Assets, Current [Abstract]
Cash and cash equivalents	292	102	1,231
Other current assets	128	18
Total current assets	420	120
Investments in and advances to consolidated subsidiaries	13,602	20,815
Property, plant and equipment - net	61	62
Other noncurrent assets	142	58
Total assets	14,225	21,055
Liabilities, Current [Abstract]
Accounts payable and accrued liabilities	143	292
Long-term debt due within one year	28	49
Other current liabilities	58	40
Total current liabilities	229	381
Long-term debt	1,456	2,235
Notes payable affiliates	8,418	9,008
Pension, other post-retirement and other liabilities	732	460
Deferred income taxes	1,597	1,683
Contingent liabilities and commitments
Equity: [Abstract]
Common stock	626	620
Other stockholders' equity	1,167	6,668
Total stockholders' equity	1,793	7,288
Total liabilities and stockholders' equity	14,225	21,055
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities	(286)	3,371	(159)
FINANCING ACTIVITIES:
Proceeds from long-term debt	75	100	595
Payments of long-term debt	(871)	(3,102)	(15)
Changes in notes payable to affiliate	(590)	1,422	227
Tax benefit of stock-based awards	22	7	1
Premiums paid on early debt retirements	(254)	(574)	0
Proceeds from issuance of common stock	49	12	6
Dividends paid	(457)	(284)	(256)
Other - net	(5)	(12)	(1)
Net cash provided (used) by financing activities	(2,031)	(2,431)	557
INVESTING ACTIVITIES:
Capital expenditures	(28)	(15)	(14)
Changes in investments in and advances to consolidated subsidiaries	2,553	(2,054)	(1)
Other - net	(18)	0	1
Net cash provided (used) by investing activities	2,507	(2,069)	(14)
Increase (decrease) in cash and cash equivalents	190	(1,129)	384
Cash and cash equivalents at beginning of year	102	1,231	847
Cash and cash equivalents at end of year	292	102	1,231
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted	233
Cash Dividends Received [Abstract]
Proceeds from Dividends Received	$ 1,200	$ 5,000	$ 635